Many vehicles have been equipped with a power train including an engine and a multi-speed transmission. The multi-speed transmission allows torque to be transferred from the engine through a wide range of vehicle speeds. The engine operates through its torque range a number of times corresponding to the number of forward speed ratios that are available in the transmission.
A variety of manufacturers have provided three speed and four speed automatic transmissions. Other transmissions have been constructed or described in publications suggesting six, seven or eight speed automatic transmissions. The increased number of speed ratios reduces the step size between ratios and therefore improves the shift quality of the transmission by making the ratio changes substantially imperceptible to the operator under normal vehicle acceleration. However, previously known transmissions providing six or more forward speed gear ratios are relatively complex, heavy and difficult to package because of their relatively large size. Furthermore, these transmissions are relatively expensive to construct due to the complex machining of multiple fluid passageways required to actuate multiple hydraulically operated brakes and clutches found within the automatic transmissions.